WATCH: Jon Stewart Just Can't Resist Making Santorum Jokes

"I vow to only ridicule Rick Santorum for his absolutely absurd and
sometimes vile political and social beliefs," he said
then.

But that was January.

Staying away from the graphic, off-color re-definition of the
former Senator's last name is harder than it seems,
apparently.

On last night's Daily Show, Stewart had to bite his tongue after
calling up news commentary about Santorum's "surge spreading" and
his new anti-Romney ad featuring a Romney impersonator shooting a
brown, muddy liquid out of a gun.

It was just too tempting.

"This is entrapment!" Stewart shouted, clearly aching to make a
"Santorum" joke.